1. Field of the Disclosure
This disclosure relates generally to production wells and detection and prediction of water breakthrough in such wells.
2. Background of the Art
Wellbores are drilled in subsurface formations for the production of hydrocarbons (oil and gas). After drilling of a wellbore, the wellbore is completed typically by lining the wellbore with a casing that is perforated proximate each oil and gas bearing formation (also referred to herein as the “production zone” or “reservoir”) to extract the fluid from such reservoirs (referred to as the formation fluid), which typically includes water, oil and/or gas. In multiple production zone wells, packers are used to isolate the different production zones. The fluid from each production zone is channeled through one or more tubings in the well to channel the produced fluids to the surface. Sand screens are typically placed adjacent perforations to inhibit the influx of solids from the formation into the well. Valves and chokes are installed in the well to control the flow of the formation fluids into the well, from the well into the tubings in the well and through the tubings to the surface. Surface treatment units separate the hydrocarbons from the produced fluid and the separated hydrocarbons are then transported for processing via a pipeline or a mobile transportation unit.
Typically, during the early phases of production from a production zone, the formation fluid flows to the surface because the formation pressure is sufficiently greater than the pressure exerted by the fluid column in the well. This pressure differential lifts the produced fluids to the surface. As the reservoir depletes, the formation pressure is sometimes not adequate to lift the produced formation fluid to the surface. In such cases, an artificial lift mechanism is often used to lift the produced fluid from the well to the surface. An electrical submersible pump is often installed in the well to lift the formation fluid to the surface. Water or steam is sometimes injected into one or more offset wells to direct the formation fluids toward the well so as to enhance the production of the formation fluid from the reservoir. A majority of the wells typically produce hydrocarbons and a certain amount of water that is naturally present in the reservoir. However, under various conditions, such as when the reservoir has been depleted to a sufficient extent, substantial amounts of water present in adjacent formations can penetrate into the reservoir and migrate into the well. Substantial amounts of water can also enter the well due to other reasons, such as the presence of faults in the formation containing the reservoir, particularly in high porosity and high mobility formations. Faults in cement bonds between the casing and the formation, holes developed in the casing due to corrosion, etc. may also be the source of water entering the well. Excessive influx of water into the well (also referred to as the “water breakthrough”) into a producing well can: be detrimental to the operation of the well; cause excessive amounts of sand flow into the well; damage downhole devices; contaminate the surface treatment facilities, etc. It is therefore desirable to have a system and methods that are useful for detecting and predicting the occurrence of a water breakthrough, determining actions that may be taken to safeguard the well and well equipment from potential damage and for taking (manually or automatically) corrective actions to reduce or eliminate potential damage to the well that may occur due to the occurrence of a water breakthrough on the well.